Air pump

ABSTRACT

An air pump for supplying secondary air into combustion systems of exhaust emission control systems. The pump is made in a unit with a generator wherein the generator shaft and the pump shaft are connected through a medium of reduction gears so that the generator and the pump may be driven at their optimum speeds. Means are provided to prevent the scattering of lubricant charged in the reduction gear housing.

United States Patent lshihara et al.

AIR PUMP Shinya lshihara; Yoshihiro Suzuki, both of Anjo, Japan Inventors:

Assignee: Nippondenso Co., Ltd., Japan Filed: Sept. 26, 1973 Appl. No.: 400,834

Related US. Application Data Continuation-in-part of Ser. No. 299,450, Oct. 20, 1972.

Foreign Application Priority Data Sept. 28, 1972 Japan 47-113258 US. Cl. 290/1; 310/263; 418/138; 417/411 Int. Cl. FOln 3/10 Field of Search 418/137, 138, 241; 417/411; 290/1; 60/30; 310/62, 263

References Cited UNITED STATES PATENTS 2/1925 Brett 418/138 1 June 10, 1975 2,243,898 6/1941 Fulcher 418/138 3,514,219 5/1920 Mitchell et a1 290/1 3,517,207 6/1970 Piech et al. 290/1 3,517,504 6/1970 Sakamoto 290/1 3,771,501 11/1973 De Dobom. 418/61 B 3,790,317 2/1974 Stanley 418/137 3,797,975 3/1974 Keller 418/137 Primary ExaminerG. R. Simmons [57] ABSTRACT An air pump for supplying secondary air into combustion systems of exhaust emission control systems. The pump is made in a unit with a generator wherein the generator shaft and the pump shaft are connected through a medium of reduction gears so that the generator and the pump may be driven at their optimum speeds. Means are provided to prevent the scattering of lubricant charged in the reduction gear housing.

1 Claim, 4 Drawing Figures PATENTEDJUN 10 1975 3 8 83,126 sum 2 CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part application of our co-pending US. application Ser. No. 299,450, filed Oct. 20, 1972.

BACKGROUND OF THE INVENTION The present invention relates to an air pump adapted for supplying secondary air to a combustion chamber of an exhaust emission control system for a vehicle engine, and more particularly to a pump of this kind constructed as a unit with a generator. I

The drawbacks inherent to prior arts are fully described in the specification of our co-pending application Ser. No. 299,450.

SUMMARY OF THE INVENTION On addition to the objects as described in the copending application, it is an object of the present invention to provide an air pump in which the lubricant charged in the gear housing and bearings is prevented from scattering so as to realize a longer service-life of the pump.

According to the invention, there is provided an air pump adapted for use in an exhaust emission control system of an vehicle engine comprising a vane shaft integral with a shaft of a generator carrying gear teeth at peripheral thereof, a pump rotor having an annular shaft, said annular shaft being provided with gear teeth formed at the inner surface thereof for speed reduction engagement with said gear on the generator shaft, a flange integral with said gear teeth of the generator shaft and providing a surface facing a wall of said annular shaft, an annular groove formed in alternative one of said wall and said surface, a packing ring accomodated in said annular groove, a first bearing means for rotatably supporting said generator shaft, said first bearing means being provided at its end adjacent to the generator with a first sealing means for preventing lubricant from scattering, a second bearing means for supporting said rotor, said second bearing means being provided at its end adjacent to the air pump with a second sealing means for preventing lubricant from scattering, an air escaping passage formed through a wall of the rotor and through an end cover of the air pump so as to connect the interior of the rotor to the atmosphere.

The features of the present invention will become apparent from the following descriptions of the preferred embodiment with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view taken along the axial line of the apparatus embodying the present invention.

FIG. 2 is a cross sectional view showing a radial cross section of the air pump as illustrated by FIG. 1.

FIG. 3 is a schematic view of the gear of the generator shaft in large scale.

FIG. 4 is a cross sectional view of the annular shaft in large scale.

DESCRIPTION-OF THE PREFERRED EMBODIMENT Thee'rnbodiment as illustrated is basically similar to the apparatus as disclosed in aforementioned copending application.

Referring to FIG. 1, numeral 14 designates a housing of ,a generator one, said housing also serves as a casing of an air pump 2.

A shaft 15 of the generator 2 is carried by the housing 14 through the medium of a bearing S, said shaft being integral with a vane shaft 17 of the air pump 2.

The shaft 1S carries a pinion 18, an axial end of which is extending radially outwardly therefrom so as to provide a flange 18a, as clearly seen from FIG. 3.

Numeral 20 designates a pump rotor which is provided at its axial end with an annular shaft 200. The inner surface of the annular shaft 20a is formed into gear teeth 21 therein as seen from FIG. 4, said gear teeth 21 being in torque transmitting and speed reducing engagement with the pinion 18. This engagement enables the generator and the air pump to be driven at their respective optimum speed of rotation.

As seen from FIG. 4, an annular groove 20C is formed in a wall of the annular shaft, said wall being opposed by one surface of the flange 18A.

A packing ring 19, which may be a rubber O-ring, is accomodated in said groove 20C.

It will be understood that the space defined by housing 14, bearing 5 for the generator shaft, bearing 24 for the rotor 20, pinion 18, flange 18A and gear teeth 21 is conveniently sealed by the provision of the packing 19 between the annular shaft 20A and the flange 18A.

Alternatively, the groove 20C may be provided in the flange 18A.

The rotor 20 is supported at one end by a bearing 24, as aforementioned, which is carried by the housing 14, and at the other end by a bearing 23 carried by the end cover 22 which is suitably fixed to the housing 14. As seen from FIG. 2, two vanes 12 are slidably hold by the rotor which has substantially annular cross section, said vanes are supported by bearings 13 which permits the rotation of the vanes 12 relative to the vane shaft 17. An aperture 22A formed in the end cover 22 provides, in co-operation with the aperture 20B formed in one end wall of the rotor 20, an air escaption passage which connects the interior of the rotor 20 to the atmosphere.

The housing 14 is provided with radiation fins at the portion surrounding the torque transmission system.

The bearing 5 which supports the generator shaft 15 has at its end adjacent to the generator 1, a seal member 5A which may be a rubber disc, for preventing the lubricant such as grease from scattering from inside of the bearing 5.

Another seal member 24A similar to that 5A of the bearing 5 is provided at the bearing 24, so as to seal the end thereof adjacent to the air pump 2.

Since the space, which is defined by the housing 14, bearing 5, bearing 24, pinion 18, flange 18A, and annular shaft 20A, is kept substantially air tight by virture of packing ring 19, seal members 5A and 24A, the lubricant such as grease charged therein is well restrained from scattering or being splashed out.

Thus, the air pump according to the present invention is free from any troubles resulting from short lubricant such as seizure of the gears, chattering of the gear upon torque variation of the generator shaft, and so on, whereby a longer service-life is realized.

The air escaption passage presented by the apertures 20A and 22A serves to maintain the atmospheric pressure within the rotor.

Were it not for this arrangement, a pressure established within the rotor may be transferred passing the packing l9 and will expel the lubricant from the bearing biasing the seal member 5A.

What is claimed is:

1. An air pump constructed in a unit with a generator and adapted for use in an exhaust emission control system of an vehicle engine comprising a vane shaft integral with a shaft of a generator carrying gear teeth at a peripheral portion thereof, a pump rotor having an annular shaft, said annular shaft being provided with gear teeth formed at the inner surface thereof for speed reducing engagement with said gear teeth on the generator shaft, a flange integral with said gear teeth on the generator shaft and providing a surface facing a wall of said annular shaft, an annular groove formed in said wall or said surface, a packing ring accommodated in said annular groove, a first bearing means for rotatably supporting said generator shaft, said first bearing means being provided at its end adjacent to the generator with a first sealing means for preventing lubricant from scattering, a second bearing means for supporting said rotor, said second bearing means being provided at its end adjacent to the air pump with a second sealing means for preventing lubricantfrom scattering, an air escaping passage formed through a wall of the rotor and through an end cover of the air pump so as to connect the interior of the rotor to the atmosphere. 

1. An air pump constructed in a unit with a generator and adapted for use in an exhaust emission control system of an vehicle engine comprising a vane shaft integral with a shaft of a generator carrying gear teeth at a peripheral portion thereof, a pump rotor having an annular shaft, said annular shaft being provided with gear teeth formed at the inner surface Thereof for speed reducing engagement with said gear teeth on the generator shaft, a flange integral with said gear teeth on the generator shaft and providing a surface facing a wall of said annular shaft, an annular groove formed in said wall or said surface, a packing ring accommodated in said annular groove, a first bearing means for rotatably supporting said generator shaft, said first bearing means being provided at its end adjacent to the generator with a first sealing means for preventing lubricant from scattering, a second bearing means for supporting said rotor, said second bearing means being provided at its end adjacent to the air pump with a second sealing means for preventing lubricant from scattering, an air escaping passage formed through a wall of the rotor and through an end cover of the air pump so as to connect the interior of the rotor to the atmosphere. 